Chem 1B
Chapter 16 Exercises
Name:_______________________
Solubility and Complex Equilibria
1. Determine the solubility in ( i ) in mol/L, and ( ii ) in gram/L of each of the following salts:
(a) AgCl, K sp
= 1.6 x 10
10
(b) AgBr, K sp
= 5.0 x 10
13
(c) Ag
2
CrO
4
, K sp
= 9.0 x 10
12
2. The solubility of calcium hydroxide, Ca(OH)
2
, in water at 25 o C is 0.51 g/L. Determine the solubility product constant ( K sp
) for calcium hydroxide.
3. A saturated solution of magnesium hydroxide, Mg(OH)
2
, has a pH = 10.42. What is the solubility of Mg(OH)
2
in mol/L? Determine the K sp
of magnesium hydroxide.
4. A solution containing 0.010 M AgNO
3
and 0.050 M Pb(NO
3
)
2
is titrated with 0.050 M NaCl solution. (a) At what concentration of Cl
-
AgCl begins to precipitate? PbCl
2
begins to precipitate?
(b) Determine the concentration Ag + in solution when the precipitation of PbCl
2
begins.

Chem 1B
Chapter 16 Exercises
Name:_______________________
5. 20.0 mL of 0.10 M Pb(NO
3
)
2
solution is mixed (reacted) with 30.0 mL of 0.10 M NaCl solution. (a)
Will precipitate of PbCl
2
form? (b) Determine the concentration of Pb 2+ that is in equilibrium with solid PbCl
2
( K sp
= 1.6 x 10
5 ).
6. Determine the solubility of AgCl ( K sp
= 1.6 x 10
10 ) and PbCl
2
( K sp
= 1.6 x 10
5 ), respectively, in
0.010 M NaCl solution.
7. Which of the following compounds the solubility is influenced by the pH of the solution?
Write chemical equations to show how pH will increase (or decrease) their solubility.
(a) PbCl
2
(b) PbCO
3
(c) CaF
(d) Ag
3
2
PO
4
(e) AgBr
8. What is the solubility (in mol/L) of Mg(OH)
2
( K sp
= 8.9 x 10
12 ) in a solution buffered at pH = 9.50?
9. What is the solubility of silver chloride ( K sp
= 1.6 x 10
10 ) in water and in 3.0 M NH
3
solution, respectively? [Ag +
(aq) + 2NH
3
(aq)
⇄
Ag(NH
3
)
2
+
(aq) , K f
= 1.7 x 10 7 ]

Chem 1B
Chapter 16 Exercises
Name:_______________________
10. The solubility of which of these compounds will be greatly influenced by the formation of complex ion ( i ) with NH
3
? ( ii ) with OH
-
? Show the equation of complex ion formation.
(a) Cr(OH)
3
(b) Fe(OH)
3
(c) Cu(OH)
2
(d) Zn(OH)
(e) AgOH
2
(f) Pb(OH)
2
11. A solution contains Ag + and Ba 2+ ions. What reagents would you use to separate and extract the two cations from the solution. Explain your choice of the reagents and the process involved.
12. A solution contains 0.0010 M AgNO
3
and 0.010 M Pb(NO
3
)
2
. Both cations may be precipitated out from solution by adding dilute sodium chloride or hydrochloric acid. (a) Which compound will precipitate out first, AgCl or PbCl
2
? Explain. (b) What is the concentration of Ag + when PbCl
2 begins to precipitate? (c) What is the concentration of Pb 2+ when AgCl begins to precipitate?
(AgCl, K sp
= 1.6 x 10
10 ; PbCl
2
, K sp
= 1.6 x 10
5 )
13. In a qualitative experiment, you are given a solution that contains a mixture of the following cations: Ag + , Ba 2+ , Cr 3+ , Fe 3+ , and Cu 2+ . Draw a flow chart to show how these cations are separated.
(Available reagents to use: 0.1 M NaCl, 0.1 M Na
2
SO
4
, 6 M HNO
3
, 6 M NaOH, 6 M NH
3
, and)